One issue that noone has mentioned is cost
Gen3 start at $6K-6.5 used incl loom and computer or just bloke and heads new with another $1K for loom and computer.
Boss 290 - there are no crate motors available but I have heard that there are are some people asking FPV to make crates available. We'll wait and see.
However used Boss 290's or even 260's are asking around $14 gorillas - ouch!
You can build a fantastic LS1 for that $$
Cheers